Freeper needs help calculating BOARD FEET (Vanity)

7/01/05

[Graybeard58]

I worked in a lumber mill in the 60s and thickness was expressed in quarters. A one inch thickness was four quarters, one and a fourth inch was five quarters etc.

[tomkat]

(before you wade through all this, check my profile)

Hardwood is normally priced per nominal (rough) board foot (BF).

If you need boards with an actual dimension of 3/4 x 4, the rough stock used to mill them to that size will be 1" thick x whatever widths the mill has on hand to cut from.
Your BF price from the mill will be based on the cost of the rough stock (nominal) plus the milling time required to reach finish (actual) size.

How a mill chooses to cull their rough stock to meet your order is their problem/job,
but if they try to tell you that they have to get your 4" width out of 6" stock and charge you accordingly, they're full of shi'ite.    

The rule of thumb is to add 1/2" to both the width and thickness dimensions of the sizes you need to end up with.

To reach actual thickness, a good mill will knock the first 3/16 of the crud/fuzz off both sides of the stock's width in the planer, then run the material through a wide-belt sander to meet your spec thickness, ready to stain.

Ripping to width is somewhat less wasteful because once the outer crud is removed from both edges, subsequent narrowing of the stock will involve the loss of ~1/8" for the width (kerf) of the rip blade plus ~1/32 after a pass over the jointer.

(with cherry and walnut running around $8/BF +/-, I do the math beforehand ;-)

As someone above stated, board footage is a volume measurement, but a nominal 1" thickness simplifies things a bit.
1 board foot = 144 cubic inches = 1" thick x 12" wide x 12" long.

So, assuming a room 22' x 10' with flooring boards at 4" wide:

Room = 22' x 10' = 220 square feet

Board = 4" x 96" = 384"/144 = 2.67 square fee

Room / board = 220/2.67 = 82.4 = 83 boards
Adding 10% for waste = 92 boards
(unless you do this for a living or are very careful, 15-20% would be wiser)

When you call the mill, specify 3/4 x 4 x 96 as the finished dimensions and tell them your nominal dimensions are:
1" x 4.5" x 96" x 92(pieces) = 276 board feet       (39,744 square inches / 144)

All that assumes plain edged boards, but if tongue/groove is what you're envisioning, the tongue will require an extra 1/2" in the stock's nominal width.
You'll need to recompute accordingly and plan on a higher BF price to cover the machining time for milling the tongues/grooves.

Are we clear now ?

[Timeout]

Yes! I just knew there was a good "wood" Freeper out there just waiting to be discovered!

One more point:
These boards are in stock at the mill. She let me look at them in her warehouse. They already have tongue & groove and a "release" pocket on the back and are milled to 4" or 6" widths and various lengths. She then quoted me the bd ft price.

Given that, would a professional assume to convert to the nominal width before ordering?

You're right about the waste allowance. Given the good price, I can afford to be generous. Thanks.

[Timeout]

BTW, I'm not placing the order. I have to give it to my cabinet man and he's going to add it to his order...all a little surrepticious.

I don't get the impression he orders in board feet...I assume he orders by board size.

Maybe the best thing to do is to tell him to order 100 planks (20% waste). Since that's the way he normally orders, I assume the mill will simply convert his order to board feet at shipment.

[tomkat]

If the stuff's already milled/ready to install and she's quoting you finished dimensions, nominal sizes needn't muddy the waters.

From the previous example:

22' x 10' = 264" x 120" = 31,680 in² / 144 = 220 BF + whatever waste allowance you decide on.

Hope that helps.
Gotta scoot - board feet await my attention here in PA

[bert]

Tomkat is correct and I am not going through the exercise again as planned. Read his piece and be proud to be a FReeper and recipient of such information.

[Timeout]

...be proud to be a FReeper and recipient of such information.

I'm always proud of FR and GRATEFUL for the resources it makes available. Thanks to all of you.

[Mo1]

Are we clear now ?

I don't have clue of what you just said

But I knew you would have the answer :0)